1. Field of the Invention
This invention relates to a novel video display apparatus and more particular to a video display apparatus which can display an image of high quality.
2. Description of the Prior Art
In a video display apparatus, such as a television receiver, a peripheral portion of a cathode ray tube is covered by a front mask. In a conventional television receiver, the front frame is used to mask a non-luminous part of the cathode ray tube only in view of the appearance of the television set and the fact that there is a textural difference between the front frame and the image displayed on the cathode ray tube is ignored. For example, a color of the front frame is selected as black or gray in a conventional television receiver, and then the hue and texture of the front frame are quite different from that of the displayed image on the cathode ray tube.
In such a conventional receiver, a viewer can not view the image with high quality for the following reasons. The human eyes have two characteristics in pattern perception: one is known as central vision and the other is known as peripheral vision. Central vision is used for recognizing meaning of a visual pattern, while peripheral vision is used for recognizing the position or movement of the pattern and thereby controls the movement of the eyes. More particularly, central vision is related to a recognition or discrimination system of the eyes, and peripheral vision is related to an eye-movement system of the eyes. Because peripheral vision controls movement of the eyes, the boundary between the front frame of the television receiver and the image on the cathode ray tube is discerned easily by peripheral vision. In watching the image on the television receiver, since peripheral vision controls the movement of the eyes, the front frame is not recognized by central vision. Thus, unless distracted, a viewer keeps his attention only on the central portion of the image, so the resolution of the peripheral portion of the image on the cathode ray tube serves no purpose to the viewer's perception of the image. Furthermore, the.
High contrast between the front frame and the displayed image on the cathode ray tube in a conventional television receiver induces fatigue of the eyes.